DE1491471A1 - Microwave amplifier - Google Patents

Description

Standard electrical system Lorenz A <|

Stuttgart-Zuffenhaus en

Hellmuth Hirth-Str. 42 '■ - » J 1491471

ISE / Reg. 2878

P.!. Farnsworth - 173

Microwave amplifiers

The priority of the April 19, 1963 filing in the United States of America is claimed

The invention relates to a microwave amplifier and more particularly to an amplifier in which the energy a beam of collimated electrons is used to generate an amplified signal. Compared to one ordinary klystron, the amplifier is more effective, smaller and lighter and has a longer life and is easier to use.

In amplifiers with speed modulation, such as a klystron, an indirectly heated cathode delivers an electron beam at a uniform average speed. A high-frequency field between the grids of the bundling cavity in the klystron changes the speed of the electrons passing through in such a way that the electrons that were accelerated through the bundling cavity in the running space the electrons that leave the bundling cavity earlier, but through the previous half-cycle were braked, overtake. As a result, the beam current between the grids of the second resonator or collector-hesonator is pulsating or bundled, and when the second resonator is tuned to the bundling frequency H.Apriii964 * 909814/0660

, Br. HlAa -2-

ISE / Eeg. 2878 145 1471

-2-, the beam delivers energy to the interceptor.

A correspondingly intense electron beam is particularly important when high output power is required from a klystron necessary, and the thermal cathode must have a large emission surface with high thermal Is subject to radiation losses. Such drilling work generally as a pulse amplifier. The pulse amplitude can be 50 to 500 times larger than the mean amplitude. The thermal cathode must be built so that it can deliver these large peak currents · As a result, the thermal cathode creates difficult cooling problems. As with any thermal arrangement, the klystron requires a warm-up time to achieve stable working conditions, and the service life is generally limited by the cathode surface. After a period of spruce use a start-up time of several hours is required.

Since in a klystron the mean energy of the electrons leaving the resonator is greater than that of the in electrons entering the resonator, the converging resonator requires a substantial amount of energy to absorb the Focus beam.

Because the running space of a klystron is naturally solid, and that Optimum concentration for a level of excitation takes place, selection and maintenance of excitation and the acceleration voltages are very critical. The one caused by the concentration of electrons in the bundles Space charge tends to disperse the bundles in the running space, causing the beam to diverge. Both the longitudinal and the transverse scattering also diminishes the effectiveness of the klystron. Therefore, with good constructions of klystrons

9098U / 0660 ~ ³ ~

a compromise between enlarging the barrel ~ space possible gain and the loss due to can be inferred from scatter. The theoretical maximum effectiveness is 58 #. Practical effects are in the Order of magnitude of 2Q # due to various secondary Bundling effects of the space charge forces. A big part this loss is, at klystrons, the heat which must be removed by external cooling arrangements. Secondary electrons that are undesirably in the area of the collector of the klystron will also decrease its effectiveness and cause other undesirable effects.

Klystrons are also undesirable frequency changes due to thermal expansion and contraction due to Subject to temperature changes »The resonance circuit of the klystron is heated by scattered energy. These Thermal expansion effects complicate the tuning of the two resonators.

These requirements for the running space and the bundling cavity and other requirements necessary for operation are avoided by the invention by a single arrangement, in which only a negligible space in connection with the emission and the bundling of the electrons is necessary, so that neither a running space nor a thermal Cathode nor the electrodes required for a klystron are required

One object of the invention is to provide a new electron discharge vessel To be provided for amplifying signals in the microwave range.

Another object of the invention is to provide a high frequency amplifier to create in which the generation and

9098.U / 0660

Bundling the electrons in more effective, reliable and easily achieved.

Another task of the. Invention is to create a Provide high frequency amplifier that generates and bundles electrons from a cold cathode source after the process, known as "phase focusing", be emitted.

Another object is to provide a high frequency amplifier that does not require any warm-up time, only negligible problems due to thermal expansion and the associated frequency change raises in the bundling cavity and greater effectiveness, Provides energy gains and degrees of amplification.

Another task is to build a high frequency amplifier to create a hollow beam for effective energy transfer generated, but reduced frequency losses caused by the bundling of the beam, the scattering of the beam electrons is reduced, requires no running space and no critical voltage settings and reduces the release of secondary electrons in the area of the collector.

Another object is a high frequency amplifier that is easy to tune and operate simply, has a theoretically unlimited lifespan and no start-up time after a period of non-use requires *

Other objects and features of the invention will be given in the following evidently on the basis of the description

-5-

9098U / 066Q

H9H71

ISE / Beg. 2878

-5-

Since there is an electrical discharge vessel according to the invention from a cavity, the two separately arranged, field-determining and electron-emitting surfaces and means for applying an alternating electromagnetic field to the space between these two surfaces to apply, has · The space between the two surfaces and the amplitude and period of this electromagnetic Alternating field are such that the electrons are phase-focused in the space. One of the electron-emitting surface is provided with an opening through which bundles of phase-focused electrons to fly. Means are also provided to accelerate this electron beam along a predetermined path and further means for extracting kinetic energy from these electron bundles when this is a predetermined one Cross the area of this path.

The invention will be explained in more detail below with reference to the exemplary embodiments in the accompanying drawings.

Pig · 1 shows a longitudinal section of one according to the invention Arrangement,

Pig. Fig. 2 shows a partial schematic section for the purpose of explanation the generation and concentration of electrons in the arrangement of the pig 1,

Pig · 3 shows a diagram for explaining the Phase focusing,

Pig 4 shows schematically the beam path and the equipotential surfaces the arrangement of the pig. 1,

Pig · 5 is a similar schematic diagram illustrating the collimated electron beam, 909814/0660

-6-

Pig. 6 is a graphical representation of the shaft within the catcher gap and serves to explain the Theory of operation,

Pig 7 shows a longitudinal section through another embodiment the invention,

Pig _# 7a is an enlarged partial longitudinal section of the coaxial lines that run at the input and output ends of the assemblies after the Pig. 1 and 7 are used,

KLg, 8 shows schematically the electron generator of the arrangement according to Figo 7 and serves to explain the Working method,

KLg, 9 shows an enlarged part of the arrangement according to FIG Pig. 8th,

Pig, 10 is a partial view taken along lines A-A of Pig. 7.

In Pig, 1, 1 an evacuated cylindrical envelope referred to, the vacuum-tight manner at its opposite ends by means of flexible diaphragms or Paltenbälgen 2 and 3 are closed, pass the vorzugsweJLs e aua oxygen-free, high conductivity copper sheet "The Diaphrag- na 2 forms the end wall of a Eingangshohlraumresonators 4, while the diaphragm 3 similarly forms the end wall of the output cavity resonator 5. The cylindrical outer walls of these cavity resonators 4 and 5 are fused in a vacuum-tight manner to the cylindrical wall of the casing 1 in a suitable manner, so that the cavities form part of the evacuated casing. The bell-shaped parts 6 and 7 are screwed coaxially onto the corresponding cavities 4 and 5. These two parts 6 and

9098U / 0660 -7-

H8U71

ISE / Reg. 2878

-7-

have a micrometer-like device for tuning of the cavities 4 and 5. While any suitable adjustment device can be used, that is Pig 1 shown consists of a sheath 8, richly screwed coaxially into the tubular part of the end part 7, and a part 10 of the coaxial line which is screwed into the sheath 8. The slope of the outer and inner The threads of the sheath 8 are such that one revolution of the sheath 8 results in a nonius-like movement of the part 10 results, e.g. the pitch of the outer thread turns 32 turns per unit of length and that of the inner 24 per Unit of length. The outer threads are arranged such that the shell 8 in the tubular Part 9 is screwed in; the coaxial part 10 moves outwardly with respect to the shell. Pure the The incline just given results in a total incline of 96 turns per unit of length. The mechanism 11 on the left side of the tube is the same as that just described and reference numerals with the subscript "a" are used for identical parts. The two pieces of coaxial line 10 and 10a are secured against rotation by the copper electrodes 12 and 13, which are vacuum-tight fused or otherwise connected to parts 2 and. The electrodes 12 and 13 are also conductive firmly connected to the outer conductors of the corresponding parts 10 and 10a. Hence, there will be a twisting of the envelopes 8 and 8a cause axial movement of electrodes 12 and 13, respectively, thereby tuning the resonance cavities 4 and 5 is reached. The diaphragms 2 and 3 are explained this movement without destroying the vacuum of the tube. The electrodes 12 and 13 are provided with bores 14 and 15 and receive the loops 16 and 17, which are isolated from the electrodes 12 and 13, respectively. Daa an end

-Ö-

9Q98U / 066Q

ISE / Reg. 2878

-8th-

this loop is connected to the center conductor of the coaxial lines and the other end to electrodes 12 and 13, respectively. The loops 16 and 17 are in the corresponding 'the cavities 4 and 5 and are used for insertion or. Decoupling of energy.

Another wall of the cavity 4 is through the disk 18 made of copper beryllium or a similar material, which is capable of emitting secondary electrons is formed. The disc 18 has a central, cup-shaped formed Part 19, which has an opening 20 which is arranged concentrically to the longitudinal axis 21 of the tube, is provided.

A dynode 22 made of copper-beryllium is conductive with the electrode 12 or pin-like material that is suitable to emit secondary electrons. The Dynode 22 has a concave surface 23 which is approximately parallel to the rear surface 24 of the part 19. Of the The radius of curvature of the surface 23 is slightly smaller than that of the surface 24. The reason for this difference becomes clear in the following description. The surface 23 is preferably partially spherical in shape and arranged coaxially with respect to the tube axis 21. The two surfaces 23 and 24f which are referred to as field-determining surfaces are arranged separately from each other and form part of the whole resonance cavity 4

On the right-hand side of the disk 18, a short, metallic lens sleeve 25 is attached. A metallic., Anode or focusing cylinder 26 is coaxial in the sleeve 1 supported and its one end is the sleeve

-9- 9098U / 0S60

■ ISE / Reg. 2878 »491471

opposite to. The anode is preferably made of getter material, such as titanium, made to absorb residual gases. The cavity 5 is constructed very similarly to the cavity 4 and has a disc 27 with a spherical part 28. This part 28 is provided with an opening 29, which is concentric with respect to the vertical axis 21. The opening 29 is much larger than the opening 20 in the entrance cavity 4. The end wall 27 is preferably formed from oxygen-free, highly conductive copper and can be provided with a gold plating, for example, in order to reduce secondary electron emission to a minimum.

10 at the electrode 13 is a cylindrical copper collector 30 connected, which is provided with a spherical surface 31, preferably with a gold plating. These Surface 31 is arranged coaxially to the axis of the ears 21 and is separated from the part 28 by a gap 32 for to form the cavity resonator 5. The size of the opening 29 is almost as large as the surface 31, so that a Minimum overlap between surface 31 and the part 28 of the wall 27 consists. The reason for this becomes clear from the following "description · A short, coaxial, cylindrical sleeve 23 is attached to wall 27 and lies at the other end of the focusing cylinder 26 opposite. A source of energy, such as the battery 34 »supplies the tube with the necessary voltage. The negative pole of the battery 34 is connected to the cavity 4, while the positive pole is connected to the cavity 5. A tap on the battery 34 is directly connected to the anode tied together. Typical operating voltages for the tube shown in Figure 1 are given in Pig * 1.

-10-

909814/0660

U9U71

ISE / Eeg. 2878

-10-

In operation, a microwave signal is of the order of magnitude of, for example, 1000 MHz to the coaxial line part 10a coupled to excite the cavity 4 · With the help of the sleeve 8a, the cavity can be tuned and on the other hand the parameters are chosen and matched so as to enable an effective adjustment between the line 10a and to ensure the cavity 4.

Similarly, a microwave circuit is coupled to the output line 10 and the cavity 5 with the aid the sleeve 18 matched. The parameters are chosen to allow a suitable match between the cavity 5 and the line 10 to achieve.

The application of the field to the gap between the two surfaces 23 and 24 results in the emission from the opening 20 of electron bundles, the length of the axis 21 and. be accelerated through the gap 32 of the cavity 5. The gap 32 serves as part of the catcher so that the passage of the electron bundle through the gap 32 results in the excitation of the cavity 5 and its generation an amplified microwave signal. This amplified microwave signal is made using the loop 17 and the line 10 are decoupled from the cavity 5. The back of the gap 32 is through the surface 31 completed, which serves as a collector for the electron bundle.

So far, some characteristics of the different parts have been identified and functions are explained, while in the following these are to be dealt with individually and then together · Bas The first feature is the pulse emitter or multiplier, which ends from the two field-determining, electron-emitters Surfaces 23 and 24 within the cavity 4 are

909SU / 0660

-11-

H9U71

ISE / Reg _e 2878

-11- -

stands. This particular arrangement essentially fulfills two different functions at the same time. These are the Emission of electrons and the bundling or phase focusing of these electrons in periodic groups, dfe are emitted from the opening 20. These two surfaces 23 and 24 can be regarded as the dynodes of a multiplier in such a way that electrons oscillate at impact speeds between these two surfaces and trigger secondary electrons. Since the secondary electrons also oscillate at the speed of impact, they generate On the one hand they are secondary electrons, so that the number of electrons is multiplied until certain boundary conditions are met are achieved. Under certain conditions the electrons become, after they travel a number of ways between the surfaces covered, bundled or, in other words, phase focused. This will be explained in more detail below explained.

In the pig. 2 and 3, in which like reference numerals are the same Designating parts is assumed to be an alternating electromagnetic field at the space between the two surfaces 23 and 24 lies. This alternating electric field is represented in Pig · 3 by the sine wave. It is on assumed that a single electron e.g. through photoemission, thermal emission or any other emission sion from point 35 in Fig. 2 starts and through the PeId is drawn against surface 24 in the path indicated by arrow 35a. When the electron is on the surface 24 arrives with sufficient kinetic energy, secondary electrons are generated. However, there are two possibilities for the secondary electrons that need to be considered. One of them is that in the moment of arising

-12-

9098 U / 0660

the initial energy is insufficient to overcome the field, which still has the same direction that forces the "primary electrons" to move towards the surface 24. Under this condition, these secondary electrons are repelled and are lost for any further action »Let us consider the second possibility, namely that the electric field changes direction while the primary electrons are just reaching surface 24, in this way the secondary electrons find favorable conditions to leave and migrate towards the surface 23. The Arrow 36 indicates this path. When these secondary electrons arrive on the surface 23, similar conditions prevail as they exist when they leave the surface 24, additional secondary electrons become generated, and this process continues, and the electron vibrations generate a multiplication of the Electrons.

In order to develop the electron multiplication, it is necessary that the electron transit time from one electrode to the other is exactly an odd number of half a period of the applied electromagnetic alternating field. Since the running time depends on the applied voltage, this condition can be achieved by changing the amplitude and / or frequency of the field. While it may appear at first that this electron multiplication is being continued ad infinitum, the multiplication may reach a limit value due to the space charge formed in the gap, as will be explained below.

The electrons that make a dynode, e.g. dynode 23, to

-13-

9Ö98H / 066O

ISE / Reg. 2878 1 H 8 Ί 4/1

leaving different moments tend to catch up with each other so that upon arriving on the opposite electrode they show an improvement in their synchronization. Repeated paths of these electrons result in a tightly bundled electron disk, which constantly increases its density and bounces back and forth between the electrodes and follows the oscillation of the applied electric field. This bundling process is known as phase focusing. This phase focusing is in Pig. 3, in which the zv / ei sine waves denote the field which oscillates between the two surfaces 23 and 24. If we first assume that an electron "a ^w leaves the surface 24 at the time" t ₀ ", it will be accelerated through the gap and will be on the surface 23 at the time" tQ ¹ ", as indicated by the symbol" a ¹ " is indicated; the time interval between tQ and t _Q 'is equal to half a period of the sine wave A, B.

It is now assumed that another electron "b" leaves the surface 24 at the time t ^. This electron starts some time after the zero point of the field and experiences a greater acceleration than the previous electron "a" experienced. This electron "b" arrives on the surface 23 at time t ₁ ', which corresponds to a little less than half the period of the sine wave. An electron "o" that _{leaves surface 24 at time t 2} arrives at surface 23 at time tp ¹ . The time interval is even shorter than that of "b ¹¹ and less than half the period of the sine wave. The distance between points a ¹ , b ¹ and c ¹ and the distance between points a, b and c shows that the electrons are at their arrival on the surface 23 are closer together than when they leave the surface 24.

-14-

8Q98U / 066Q

-H-

As the cycle continues, the ^{electrons labeled a 1} , b 'and c ¹ arrive on surface 24 at a ", b ¹¹ and c ¹¹ and are even closer to one another than they were on surface 23, so that it is apparent becomes that, after a multiple repetition of the cycle, all electrons arriving on the surfaces 23 and 24 are synchronized, so the electrons can be viewed as densely bundled or phase-focused.

It can be assumed that all electrons emitted from the two surfaces 23 and 24 achieve phase synchronism. However, this is not necessarily the case. An analysis of the Pig3 shows that only about 35% of the field period (this 35 ° includes the period between t and ± 2 ) is effective for focusing the electrons. In other words, electrons emitted from one of the surfaces 23 and 24 in phase with this 35 ° part may be bundled, as has just been stated. However, electrons that were emitted at a different time in the period experience a deceleration rather than an acceleration field and in this way give up their energy to the field.

If we look at Figo 2, we assume that the electron multiplies fanning takes place between the surfaces 23 and 24 in the direction of the arrows, the electrons, when they have reached the vicinity of opening 20, emitted cyclically approximately in the form of a ring. The greatest electron density Jst on the periphery of the rings. The emission takes the form of hollow electron rings 37 like this is indicated schematically in FIG. The distance between these rings, the electrons of which are tightly bundled,

9099U / 0660 ~ ¹⁵ ~

ISE / Eeg. 2878 I 49 I 4 / Ί

speaks of the frequency of the exciting field.

As a result of the various voltages applied to the parts of the tube, equipotential surfaces are formed, similarly as shown in FIG. An electron lens is provided between the surface 24 and the anode 25, which the electron bundle 37 focused on the axis 21. These electron bundles are referred to as beam 38 in the following. However, as the beam advances, it experiences the action of the lens between the anode 26 and the collector 28 and 31 and possibly goes through the opening 29 through the gap 32 and is collected by the surface 31. Also, as part of this beam focusing, note that the dynode is symmetrically curved with respect to the axis 21 is. This is important for the reason that secondary electrons reach the surface 23 with an approximate Maxwell's Leave speed distribution and a medium one Energy of about 10 volts and directions according to the Lambertian distribution. Both the speed and the directional distribution are remarkably independent on the energy and the angle of incidence of the primary electrons. The secondary electrons, which ultimately go through the opening 20, leave the surface 23 in a perpendicular manner Angle to it. Since the surface 23 forms an angle with the axis 21, the initial electron movement is convergent. So there are two converging forces acting on the emitted electrons, one due to the focusing anode 26, as already stated, and a second due to the speed and directional distribution of the electrons after leaving the surface 23. This convergence is extremely important because it is a closer packing which causes electrons in the bundles 37 and reduces radiation losses.

9098U / 0660

-16-

According to Fig. 2, the multiplied electrons migrate radially inwardly against the opening 20 for various reasons »1) they experience an attraction of the field from the Anode 26 and are therefore drawn through opening 20,

2) Space charge recoil tends to oscillate Electron cloud in space 23a to it, the bundle after move inside,

3) the electrode 23 has a smaller curvature than the surface 24, as already mentioned earlier. As a result, induce the field forces the electrons to move against the tube axis.

The combined effect of these three forces results in the emission of the bundles 37.

A second limiting factor on the final number of emitted electrons are the space charge effects. To maintain the multiplier process, the secondary emission factor of surfaces 23 and 24 must be greater than 1. The electron cloud forms through the multiplication process of the impinging electrons twice every field cycle. This leads to the assumption that the increase in the number of electrons produced is unlimited. However, it is reached in a state of equilibrium when the electrons produced are close to the boundaries of the surfaces 23 and 24 encounter a large space charge field, which prevents part of it from uniting with the electron cloud and ultimately on the opposite surface to hit »when this space charge limit is reached is, only one electron can be generated for each incident Electron to overcome the raiam charge field. The additional / Secondary electrons are borne by the emitting surface

-17-9098U / 0680

1 L 9 1 L 7

ISE / Reg. 2878 · H 3 I «» / I

-17-

surface driven back. In the gap 23a through the two multiplier surfaces 23 and 24 is determined, three processes take place simultaneously. These are

1) Electron multiplication on the surfaces,

2) energy transfer from the field to the moving space charge,

and

3) the space charge processes that limit the final electron density.

These processes balance each other out to create a stable, independent one To ensure the way of working, which can be described as dynamic equilibrium.

The multiplication between the two surfaces 23 and 24 can essentially be seen as a constant stress process to be viewed as; the voltage needed to multiply is such that the electron transit time corresponds to the half-cycle of the applied spanning.

It should be noted that two types of multiplication are possible.

1) the multiplier can be designed and operated in such a way that the points of impact of the electrons of the 1st, 3rd, 5th, etc. Path are well separated · There are only a few electrons at the input end 23b of the gap 23a, their number grows towards the output end 20. As more electrons are introduced at the entrance end, the number of electrons increases Output electrons. The multiplier works as an electron multiplier. So that the electron emission a is an accurate representation of the electron entrance, the space charge should be low even at the exit end 20.

909814/0660 ~ ¹⁸ ~

ISE / Eeg. 2878

-18-

However, this is not the way in which the multiplier of the invention operates. I ^{1 For} this Pail it must be considered that the secondary electrons can have any direction at a certain point of the emission, although the majority leave the surface vertically. so that the different levels of multiplication are not exactly separated. If the multiplier also works in space charge saturation, space charge will even have to be assumed at the input end 23b and additional electrons which it is possible to penetrate will in most cases have no effect. Although the electron output does not represent the number of electrons penetrating at the input end 2 ^ b, it still depends, as already explained, on the amplitude of the high-frequency input voltage. In this way the arrangement is a voltage amplifier and this is the desired mode of operation.

Now consider the "noise" to which this amplifier is subjected. There are different sources of noise:

Electrons that happen to appear at the input end 23b can affect the operation of the multiplier type but not, notable for the type of amplifier. Through the Fluctuations according to the electron temperature of the source ^ cavity 4) caused by noises reduces the space charge in the amplifier far more than is the case in ordinary thermal tubes of the Pail. Sounds, those generated by ions entering the entrance end 23b or generated in the gap 23a can be considerable. will. However, these ions migrate towards the highest electron concentration at the output end 20 and v / ground through the

-19- 9Q98U / 0660

ISE / Reg. 2878 I 491 4/1

Electrons trapped, creating the associated Noise can be reduced.

In this way the amplifier is relatively noiseless.

Further features of the invention will become clear when the amplifier is viewed as a circuit. As shown in Fig. 4, the equipotential surfaces at the opening are somewhat curved. The field of the anode helps to pull the electron groups 37 out of the opening 20. A desirable construction is one in which the gradient at the exit surface of the multiplier (central part of the surface 23) exceeds that within the gap 23a. In this case, the electrons leaving the opening 20 are not limited by the space charge, although the current within the gap 23a is space charge limited. The cavity has a high "Q" as long as it is unloaded. The ¹¹ Q "is reduced, however, when the space charge forms in the gap 23 and even more when electrons fly from the opening 22 into the anode 26. The result is the same as when an equivalent resistance is provided with the two surfaces 23 and 24 adjacent to opening 20. The value of this resistance decreases as the number of electrons in the multiplier increases.

When the voltage supplied by the input loop 16 becomes, becomes larger, the resistance becomes smaller unfl the voltage at the gap 23a increases less in relation to the increase in the input voltage and corresponds in this area nor the high frequency amplitude. In other words, the variable output load has an oervo effect, which

-20-909814 / 0660

ISE / Reg. 2878

-2 θα en amplifier linearized.

Two additional observations can be made.

1) depending on the energy range in which the tube works (e.g. between 1 to 50 or 10 to 500 watts) the mean value of "Q" of the cavity and therefore the exact size of the coupling loop 16. It is known that this loop is used to connect the cavity to the coaxial line inlet adapt. Therefore this loop has to be constructed for the desired energy range.

2) Since the field of the anode 26 penetrates somewhat into the space 23, some power is supplied from the anode 26 · Diee will be explained in more detail later in connection with the arrangement according to Pig · 7.

It should be noted that while the arrangement ^ 5 according to the Pig 1 a cavity resonator 4 for the application of the Peldes is used on the multiplier gap, other conventional arrangements are possible. In the embodiment a loop is provided for coupling, but a probe, coaxial line, a waveguide input and other means of coupling can be used

As already stated earlier, a beam 58 of electron bundles 37 is emitted from the multiplier opening 20. This beam flies through the tube to the interceptor 28, 31 along a path as shown in Pig. 5 is denoted by 38. The collecting and diverging lenses described earlier are partly responsible for this porm of the ray. The path of the beam is determined by the cargo

909814/0660

-21-

U9U71

ISE / Reg. 2878

-21-

Effect between successive electron bundles influenced. However, it can be caused by positive ions that

-8'-9 mer are in the tube, even if the pressure is 10 to 10 mm Mercury column. These ions in the main space of the tube are from the point of view of noise Seen from here, less harmless than those in space 23a. They tend to become in the space charge bundles 37 collect or, preferably in radial directions, to oscillate with them. You might think that this might be through Recombination can be removed. However, this is a less recommendable means than the charge exchange between Ions and neutral molecules. In the latter case, a new log. formed, which however has less energy than the previous one, which is now neutral and radially moves away and impinges on the anode 26 or the tube walls. It is therefore preferred that the anode be made of titanium or a similar material or to cover it with a suitable getter in order to absorb residual gases.

As already stated earlier, the beam 38 is possibly.

collected by the electrode 31 after passing through the gap 32. The electron lenses are designed so that the beam entering the gap 32 sweeps past the edges of the opening 29 as closely as possible. Since the beam 38 consists essentially of ring-shaped electron bundles, it follows that the strongest electron concentration is immediately adjacent to the gap 32 which is to be excited electromagnetic field _to follow has. As in the case of receipt

9098U / 0660 ~ ²² ~

of the tube, the gap 32 must also be connected to the output line 10 must be adjusted before the maximum effectiveness is reached istβ The cavity 5 must have the period of the Gap 32 going electron bundle to be in resonance

Since the electron bundles are accelerated on their way from the emitter to the collector, they take up a substantial amount of kinetic energy. This kinetic energy is absorbed in the gap 32 and a resonance field in the cavity 5, which roughly corresponds to that in Pig, 6. The fact is important that the electron bundle after entering the gap 32 experience a return force of the generated field, such that the bundles, which impinge on the surface 31 have a significantly lower speed. The remaining speed is just enough for the surface 31 to collect the electrons. Although the kinetic energy the electron bundle may be very high when passing the gap 32, these bundles are generated when they strike on the surface 31 no secondary emission due to the energy absorption and reduction of the electron velocity. In addition, the DC collector voltage is selected so that there is no multiplication at a certain gap width can take place. This explanation is of course idealized, since certain boundary conditions exist which, if exceeded, can generate low secondary emissions.

One method of controlling electron collection on surface 31 is to provide a suitable resistor in series with the positive terminal of battery 34 (Fig. 5). Let us assume that the collection of electrons on the surface 31 generates a current in the sighting of the arrow, which is directed to G ₁ -Un

9098U / 068Ü _23-

■. • ■; 5 «- ^r H9U71

ISE / Reg. 2878

when 40 the tension on the surface 31 was lowered. This lowered tension corresponds to the hatched increase 42 in the negative branch of the wave of FIG. 6. Since the electrons now arriving in the gap 32 through the negative increase encounter 42 enlarged negative field, they are slowed down more than before, so that they are with less Speed hitting the surface as before. This more negative build-up on the surface 31 grows until the electrons are collected by the surface 31 and the current indicated by the arrow 41 reach a state of equilibrium, which then one Subject to self-control.

A preferred exemplary embodiment of the invention will now be described in FIGS. 7, 8, 9 and 10. There a large number of parts that correspond to the arrangement of the figure are given the same reference numerals for the same arrows used·

The main differences between the two arrangements are the pulse emitter, the focusing anode and the collector. In -Bezug to the pulse emitter, which in Fig. 1 consists of two axially spaced-remote surfaces 23 and 24, the pulse emitter of Fig has. 'Faces 7, two coaxial, radially spaced-annular upper. The latter pulse emitter comprises a dynode element 37b of cylindrical shape, which is firmly and conductively connected to the electrode 12. This dynode element is coaxial with the tube axis 21 and terminates with a flat surface 38b that is perpendicular to the axis 21 The outer periphery of the element 37b, which is immediately adjacent to the surface 38b, is provided with an annular constriction, the surface of which is curved

9098U / 0660 -24-

is.

The plate 18 of the cavity 4 has an annular part 42, the inner surface 43 of which is curved. The two to each other concave annular surfaces 39 and 43 are coaxial with the axis of the tube and are radial to each other Distance on.

The surface 43 has a surface extension 44 which, as the figure shows, diverges. This surface 44 is preferably frustoconical and has an angle of approximately 15 ° with respect to the axis.

Used in place of the cylindrical anode 26 of FIG these. Arrangement of two axially separated and insulated anode sleeves 26a and 26b, the ends of which are opposite one another. Three ceramic or similar rods 26c, which are arranged at a distance of 120 ° from one another, are firmly connected to the sleeves 26a and 26b. These rods are attached to the plate 27 in a suitable manner, for example by means of Mets and sleeves 33, firmly connected.

In operation, surfaces 39 and 43 define the multiplier gap and are therefore formed from a suitable secondary emissive material which is the same as used for surfaces 23 and 24 of the arrangement of FIG. An exciting field is attached to the cavity 4 in the same way as this already in connection with FIG. 1 was carried out. The tuning mechanism 11 is operated as long as until resonance is achieved. At the multiplier gap arises an alternating field that is multiplication and phase focusing

909814/0660

-25-

of the electrons emitted by the dynode surfaces 39 and 43 have resulted. Due to the positive potential of the anodes 26a and 26b, they migrate in the multiplier gap generated electrons in the direction indicated by arrows 45 in Pig * 8 until they finally reach the annular opening 46 leaving the gap as a converging beam 38a composed of annular electron bundles 37a is composed. The anodes 26a, 26b Juat

(UBJUl

together with the pulse emitter as well as with the arrangement after the pig. 1 an electron lens which initially focuses the beam against the axis 21a. The acceleration voltages however, the anodes 26a and 26b can be changed differently, thereby making the focus more suitable Way can be influenced. Suitable signals can also be sent to these anodes for the purpose of modulating the beam 38a be placed.

The dynode element 37 is arranged axially so that the last impact of the oscillating electrons between the dynode surfaces 39 and 43 hits the surface extension.This is important, as has already been explained earlier, for the reason that the secondary electrons, which leave the surface extension 44 have an approximate Mastwellian velocity distribution and a Lambertian Hichtung distribution. The velocity distribution has an average energy of about 10 volts and the directional distribution is essentially perpendicular to surface 44. The electrons which, as in the arrangement according to Pig. 1, are phase-focused, finally ötarten from the surface 44 in the direction corresponding to the arrow 47 »so that the initial electron emission runs in the direction towards the axis 21 or, with

9098U / 0660

2878

in other words, they are converging. Even after leaving the surface 44, the electrons are still under the influence of the high-frequency field of the gap, which accelerates them towards the axis 21. The combination of these effects results in the formation of the converging beam 58a, which results in more densely packed beams 37a and thereby avoids radiation losses that the beam is kept away from the wall.

The preceding discussions with regard to the generation of electrons should now be considered aiiSax ^ BräiiaBaiK from the point of view the bundling of electrons can be considered

There are three different ways to form dense bundles.

1) Velocity modulation, as known from the klystron is,

2) phase focusing, as previously described, as one repeated form of speed modulation,

3) Secondary emission, in which additional electrons are continuous be generated·

The latter two processes are at the multiplier of the invention used, through which all electrons are ultimately bundled within the gap (fig. 7). At this Point of discussion is it good, the working methods of the pulse emitter the ζ egg arrangements of the pig. 1 and 7 to be considered and compare. In both cases the opposite surfaces are (23 and 24 in Figs. 1 and 39 and in fig. 7) have the same potential, but have a high-frequency potential difference between them. This results two types of multiplication, as follows:

9098U / 0660 ~ ²⁷ ~

ISE / Reg. 2878 1 4 9 H 7

The first type is due to the absence of an anodic

Equal field between the two surfaces, while such a field is present in the second type. In the first kind (Pig. 1), in which a small or there is no anodic constant field in the gap between the two surfaces 23 and 24, the Elektro_ multiplication:

a) Electrons that leave one surface must be enough to get on the opposite surface with enough Energy impinge to trigger secondary emission with a secondary emission factor greater than 1, through which High frequency field are accelerated,

and

b) when the electrons hit the second surface, may

the high frequency field has no direction or intensity, which prevents the emission of secondary electrons.

In the second species ^ Pig. 7) is, as explained later, a anodic field between surfaces 39 and 43 is present. The electron multiplication requires the same High frequency field conditions of Para * ä), but is more or less independent of those of paragraph b). However, an improvement in the effectiveness is achieved.

As stated earlier, those electrons are which are emitted within a certain phase range, phase focused and those who are outside of this Angles are emitted, return to the emitting surface and are lost. When introducing the mentioned anodic field, however, the latter become electrons are not reversed by the high-frequency field and are lost, but they are replaced with the phase-focused electrical

9098U / 0660 - ₂ 8-

united. The anodic field ensures electron emission at all times and, if it is sufficiently strong, even against the returning forces of the high frequency field. This is explained as follows:

The positive field created by the focusing anode 26a penetrates the gap between the surfaces 39 and 43 approximately in the manner shown schematically in FIG Field within the gap, roughly around its center, appears to the electrons as an anode, in such a way that they after the emission are accelerated against the opposite surface. Electrons. That are outside at a time of the phase range mentioned are retained by the high-frequency field instead of being accelerated to. will. They do not reach the opposite surface and turn against under the influence of the anode field the first anode back. In doing so, they are further delayed by the high-frequency field. This vibration continues without to reach surfaces 39 and 43, however, the electrons migrate towards opening 46. This condition is true illustrated by the dashed, serpentine-like arrow in FIG. However, some of these electrons can before they leave the opening 46, decelerated enough so that they fall into step or, with others V / orten, -in the phase range in which the electrons are focused. This is indicated by the solid arrow 45a in FIG Fig. 9 reproduced. This makes it clear that those electrons which are more retarded as well Find acceleration forces, possibly swing, or in other words - are "quasi-phase-focused", in one, a phase relationship with the high frequency field in which they are united with the phase-focused electrons.

9098U / 06S0

H9U71

ISE / Reg; 2878

-29-

Substantially all of the surfaces exited 39 and 43, electrons emitted the opening 46 in the form of bundles 37a and all electrons which are initially outside of the focusing phase range were emitted, are not lost. When a central anodic field is provided so that electron emission against the high frequency field can take place, work is done by these electrons against the frequency field, and the energy the latter is thereby enlarged. This serves to strengthen the high-frequency field or on the other hand Replacement of the energy withdrawn from the field during phase focusing, thereby reducing the amount of energy required for the multiplier required is reduced. The multiplier is therefore an efficient generator of electricity. While using of the central anodic field acts on the electron transit time, this effect is easy by changing the distance the multiplier surfaces and / or the cavity tuning compensates. The bulges of the dynode surfaces 39 and 43 are to some extent related to the voltages of the anodes 26a and 26b. This relationship is such that the bulges can be increased if the anode voltages are increased in order to obtain space charge saturation. The opposite condition is right, too.

While the surfaces 39 and 43 in the preceding with curved cross-section have been shown and described, it is clear to those skilled in the art that they are also flat or of can be of a different shape. The shape of the surfaces 39 and 43 depends to a large extent on the construction and the Requirements of the hearing arrangement.

-30- 909814/0660

1 L 9 1 L 7

ISE / Rego 2878 I 4 3 I «♦ / I

-30-

The catcher of the Mg. 7 is very similar to that of the Figo 1, but differs essentially in that the structure of the collector and the cavity end plate. Of the Catcher 30a is similar with a curved surface 31a the surface 31 in Fig. 1 provided »In the collector 30a, however, a coaxial, cylindrical bore 48 is provided, which extends into the electrode 13a · The open or upper end is with an open grid or conductive screen 49 is provided, which is conductively connected in a suitable manner to the collector 30a. The end plate 27 is flat and has a coaxial opening 29a of smaller diameter than the opening 29 of FIG Mistake. This opening 29a has approximately the same diameter as the bore 48 and has in one embodiment approximately 12.7 mm in diameter.

the dimensions of the remaining parts of the tube are given below.

9098U / 0660 COPY

-31- H91471

ISE / Eeg. 2878

The operation of this catcher is essentially the same like that of Fig. 1, except that the beam 38a is of such a size that it clears the opening 29a and the opening in the bore 48 just fills. The cavity 5 is made by the elect:

nenbündel 37a when they pass through the gap between the plate 27 and the surface 49 and surface 31a are excited to pass through, as is the case with the arrangement of Figure 1. Because secondary emission is to be avoided or reduced by the collector, both the surface 31a and the mesh material 49 is preferably with provided with a gold plating. Those penetrating the mesh material 49 Electrons hit the wall of the bore 48 and are at least partially collected. If any secondary electrodes are emitted from the wall, most of them become trapped within the bore and traverse it radially. If a Space charge is formed, the electrons are pushed back against the wall and thereby collected. To the secondary emission the wall is preferably provided with a gold cover. The disruptive effects of the secondary emission within the Interceptors are either prevented or greatly reduced.

From what has been said so far it can be seen that the operation (with respect to both arrangements) can take place instantaneously, since no thermal cathode has to be heated. Farther are those from the multiplier opening when using the multiplication process emitted electron bundles or electron rings tightly packed. This has an effect of working as a result, since fewer scattered electrons occur in and between the bundles. In addition, the longitudinal distance between the pulse electrode and the collector used to accelerate the electrons which means that greater kinetic energy can be communicated to them, so that when they reach the catcher "through a large output power can be drawn from the bundle. Since the velocities of the electrons, which the surface 31 reach, is relatively small, little energy is absorbed by this surface 31, which is converted into heat. The surface 31 and thus also the collector 30 operates at a low level

9098U / 0660- ~ ⁵² ~

COPY
BATH ORIGINAL

~ ⁵² - U9U71

ISE / Reg. 2878

Temperature and does not require the use of special cooling arrangements. Do not slide a thermal current into the tube
their operation is limited, the energy that is developed is
can, also not limited, except for the dissipation of 4 heat, which is generated within. It is important that the resistor 40 is located outside the tube in the figure, thereby keeping some of the heat away from the tube which would otherwise be developed on st ± H of the surface 31 ·

As can be seen from the foregoing, the size, shape, dimensions and working conditions can be changed without the invention
to leave. Some dimensions are given below for the exemplary embodiments and it should be noted that these dimensions are to be regarded as an example and not as a limitation.

Distance between surface 23 and 24 4.5 mm

Radius of the surface 23 31.7 mm

Radius of the surface 24 37.3 mm

Diameter of the opening 20. 18.9 mm

Operating frequency, approximately- 1000 MHz

Impedance of the line part 10a 50 ohms

Width of the gap 32 4.5 mm

Radius of the surface 31 31.7 mm

Radius of the / pfatte 28 adjacent surface 37.3 mm

Diameter of opening 29 38.1 mm

Diameter of the opening 29a ■ 12.7 mm

Diameter of the bore 48 15.9 mm

Hole depth 48 20.7 mm '

Widest distance between surfaces 39 and 43 4.8 mm

Distance between surfaces 39 and 43 at the edges 3.15 mm. Axial distance of surface 38b from the endplate

(Fig. 7) 25.4 mm

15.9 mm

Figures 1 and 7 are shown so that other dimensions,. can be taken directly from these drawings if required.

9098U / 0660
Copy

Claims (1)

DrI 91471 Claims Electrical discharge vessel in which the emission from an emission electrode emitted electrons are accelerated along a predetermined path against a collector, which the electrons and generates an electrical signal corresponding to the electrons, characterized in that the emission electrode has a Gap, which has at least one surface with a secondary factor greater than 1, and the high-frequency field applied to the gap the emitted electrons within the gap focussed into periodic electron bundles that point towards the catcher will be accelerated. Electrical discharge vessel according to Claim 1, characterized in that that the gap, of the surfaces of which at least one is shaped such that the dimension of the gap in a predetermined Direction has at least one change, works as a resonance gap, .in which as a result of the field lying on it between the vibrating surfaces becoming more and more phase-focused Secondary electrons move essentially in a certain direction within the gap. Electrical discharge vessel according to Claim 1 or 2, characterized in that that the gap is determined by a pair of surfaces facing each other at some distance, of which at least one consists of a material that has a secondary emission factor greater than 1. Electrical discharge vessel according to at least one of Claims 1 ... 3, characterized in that for accelerating the electron beam an anode is used, which makes the electron bundle convergent. Electrical discharge vessel according to at least one of Claims 1 ... 4, characterized in that the from the emission electrode generated electron beams have a ring-shaped iorm, so that a hollow jet results. Electrical discharge vessel according to at least one of the claims 1 «#. 5f characterized in that the emission electrode is a Is an electron multiplier that emits electron beams. 909814/0660 copy ~ ⁵⁴ ~ -34- H9-H71 ISE / Reg. 2878 7. Electrical discharge vessel according to at least one of the claims 1 ... 6, characterized in that in or between one of the one or more surfaces defining the gap an opening is provided, which is arranged such that the phase-focused Electron bundles move through this opening against the "accelerating electrodes". 8. Electrical discharge vessel according to claim 3 in combination with at least one of claims 4 ··· 7, characterized in that each of the surfaces defining the gap is curved and each has a different radius of curvature, so that at least there is an area where the surfaces are further apart. 9. Electrical discharge vessel according to claim 3 and 7 »characterized in that that the opening is arranged in one of the 2 surfaces defining the gap. 10. Electrical discharge vessel according to claim 3 and 7 »characterized in that that the opening is formed by the edges of the two surfaces defining the gap. 11. Electrical discharge vessel according to at least one of the claims 7 ·· »10, characterized in that means are provided to . the phase-focused electron beams against and through the opening to move. 12. Electrical discharge vessel according to at least one of the claims 7 - .. 11, characterized in that the acceleration of the The cylindrical anode used in the electron beam has an axis perpendicular to and through the plane of the opening Center goes and one end of the anode is adjacent to at least one of the surface defining the opening. 13 · Electrical discharge vessel according to claim 3 and 12, characterized in that that both surfaces defining the gap are concave with respect to the anode. 14. Electrical discharge vessel according to at least one of claims 1 ... i3 _t, characterized in that the electric field is generated by a resonance circuit, for example a resonance cavity in which at least one of the surfaces determining the gap represents the main part of the circular capacitance 9098U / 0660 -35-COPY
ORIGINAL INSPECTED H9H71 ISB / Regc2878 ~ ⁵⁵ - 15. Electrical discharge vessel according to at least one of the claims 1 ... 14, characterized in that the collector electrode with ^: a gap determined by at least one surface, and at least one of these surfaces has a secondary emission factor greater than 1 and at least one of the surface defining the collecting gap is provided with an opening which is arranged such that the accelerated phase-focused electron beams in the Catcher gap, which acts as a resonance gap for absorbing energy from the elec- . Tronenbündeln serves. 16. Electrical discharge vessel according to claim 15 »characterized in that the catch on it gap through a first and a second acadtx. surfaces arranged separately opposite one another is determined, of which the first is provided with an opening for the passage of the accelerated electrons onto the second surface, the plane of which is perpendicular to the center of the predetermined path of the electron beam and that the second surface consists of a material whose secondary emission factor is less than 1. 17 · Electrical discharge vessel according to claim 16, characterized in that that the two surfaces of the collector electrode form a resonance gap which is shaped and dimensioned in this way. through the ' that he electron beams flying through the / opening of the first surface is excited. 18. Electrical discharge vessel according to claim 16 and 17, characterized in that that the second surface is a solid, concave surface. 19 Electrical discharge vessel according to Claims 16 and 17, characterized in that that the second surface for receiving the beam is provided with a cavity which is in relation to the opening the first surface is arranged so that the electrons penetrate into it and are trapped. 20. Electrical discharge vessel according to claim 19 »characterized in that that a cover made of a preferably conductive mesh material is provided over the cavity. 9 0 9 8 U / 0 6 6 0 COPY
ORIGINAL INSPECTED ~ ³⁶ ~ U9U71 ISE / Reg. 2878 21. Electrical discharge vessel according to claim 3 and 6, characterized in that that the edges of the two surfaces determine the opening, which is arranged and shaped in such a way that the electron beams fly through it onto the acceleration electrodes. 22. Electrical discharge vessel according to claim 21, characterized in that that the two surfaces defining the gap of the emission electrode are arranged coaxially and radially separated from one another and the surface closest to the acceleration electrodes has an annular surface extension that extends outward diverges. 23 · Electrical discharge vessel according to at least one of the claims 1 ... 22, characterized in that the acceleration electrodes is formed by a tubular anode divided into segments and each of these segments is provided with a different bias voltage is. 24. Electrical discharge vessel according to at least one of the claims 1 ... 23, characterized in that the potential of the acceleration electrodes A positive potential gradient is generated in the emission gap, through which the electrons against the acceleration electrodes be accelerated April 14, 1964
Dr Hi / La / Rp 9O98U / iU? .6O